1. Field of the Invention
The present invention relates to a hoisting assembly and, more particularly to a hoisting crane of the jib type having a jib boom and a counterweight arm.
2. Description of the Prior Art
In hoisting assemblies having a jib boom and a counterweight, said counterweight is generally in fixed relationship with the supporting means to counterbalance the force due to the load which is hanging from the jib boom. In such assemblies, the torques due to the respective weights of the counterweight and of the load counterbalance one another solely for a precise weight of the load. When the load does not have exactly this weight, it results therefrom a tipping over of the jib boom and counterweight arm assembly with respect to the supporting means. In such an assembly, it is then necessary to provide either a supporting structure which ensures the assembly to be stable even in spite of the tipping over torque, or mass means disposed upon the structure, generally at its base, to counterbalance said tipping over torque.